As shown in the above perspective view of the orbits, S/1997 U 1 =
Caliban = U XVI (green) has almost exactly the same orbit as S/1999 U 2 =
Stephano = U XX (magenta). S/1997 U 2 = Sycorax (light blue) and
S/1999 U 1 (Setebos) have very similar orbital planes, though the orbit
of Sycorax fits well inside that of Setebos. The inclinations of all five
satellite are very similar (from 141 to 153 degrees). So far, at least,
Uranus appears to have only one family, of retrograde irregular satellites.
This is quite different from Jupiter and Saturn, which have retrograde and
prograde irregular satellites.